Horizontal boilers,apparatus in combination therewith and methods for heating same



Aug. 26, 1969 J. T. vooRHEls 3,463,125

HORIZONTAL BOILERS, APPARATUS IN COMBINATION THEREWITH AND METHODS FOR HEATING SAME Aug. 26, 1969 J. T. vooRHEls 3,463,125

HORIZONTAL BOLLERS, APPARATUS IN COMBINATION THEREWITH AND METHODS FOR HEATING SAME Filed Nov. 16, 1967 5 Sheets-Shea?l 2 FIG. l b. r@ um?? bia- "MHW" @gew/ 15m Mfr Aug. 26, 1969 J. T. vooRHEls 3,463,125

HORIZONTAL BOILERS, APPARATUS IN COMBINATION THEREWITH AND METHODSA FOR HEATING SAME Filed Nov. 1e, 1967 5 Sheets-Sheet 5 ,f iG-@GQfe-@ t @Quo-QU@- United States Patent O HORIZONTAL BOTLERS, APPARATUS IN COMBI- NATION THEREWITH AND METHODS FOR HEATING SAME James T. Voorhes, 105 Rensselaer Road, Essex Fells, NJ. 07021 Filed Nov. 16, 1967, Ser. No. 683,690 Int. Cl. F22b 9/12 U.S. Cl. 122-88 12 Claims ABSTRACT F THE DISCLOSURE A horizontal boiler comprising an elongated first shell having a sheet at one end and a stack breeching extending from said end and beyond said sheet, with or without an economizer section therebetween, a directfired second shell in and spaced from the first shell and having a sheet at one end, flue tubes spaced from each other and said first shell and connected to the sheets at openings therein, thereby providing a convection section including passageways in communication with the interior of the second shell and the stack breeching and also space for water and in communication with the space for water between said shells, and a water storage and steam drum above the first shell, means for the passage of water between the drum and first shell and means for the passage of steam from the first shell into the drum; and means for feeding water-treating chemioals to the water. Also shown are means in the second shell for aiding in the combustion of fuel preferably supplied into the second shell from means located at one end of the second shell for internal direct-firing. The convection section, the economizer section `as well as the stack breeching are in alignment with said second shell, and the flue tubes of said sections, and the means for aiding combustion are all disposed interiorly of said first shell. The method comprising into the second shell feeding flaming fuel, which flame terminates upstream of the fiue tubes.

Cross-reference to related application Copending 'U.S. `application Ser. No. 548,451 filed May 9, 1966, now Patent No. 3,367,384.

Background of the invention The invention is directed to novel horizontal boilers for steam by ultilizing a steam drum in combin-ation with steam producing apparatus.

Prior to the present invention, the industrial steam boilers may be divided into two main categories: firetube and water-tube. The fire tube boilers of the Scotch type include an elongated fire receiving furnace extending through enlarged openings in each of Ia pair of spaced sheets to which are secured a plurality of tubes parallel to and extending the full length of furnace and also bafiies to provide a number of convection sections which includes said tubes for multi-passing of the hot gases first in one direction through one section, then in the opposite direction through an other section, etc. Thus the hot gases first passing through one section increases the temperature of the tubes thereof to an average value and then in passing in the opposite direction through another section increases the temperature of the tubes thereof to an average value significantly lower than said first mentioned value. As a consequence due to the obvious difference in the expansion rates of the tubes of one section with respect to those of the other section tubes work with respect to the sheets whereby leaks occur at the connections between the tubes and sheets. The problem is aggraviated by frequent changes of r- 3,4'63,125 Patented Aug. 26, 1969 ice ing rate. Still another disadvantage of said boilers is that their diameter is limited as is the overall size of the boiler as well as the steam output. Such boilers have the further inherent disadvantages of high water storage and the entire storage must be initially heated slowly to prevent internal stresses.

Summary A horizonal boiler comprising a first elongated shell, a stack breeching connected to one end of said shell, with or without an economizer convection section therebetween, a furnace, internally direct-fired, comprising a horizontal second shell in and spaced from said first shell to provide a first space for water therebetween, a first sheet secured to said second shell at one end thereof, a second sheet disposed between said first sheet and a wall of sad stack breeching and secured to said first shell at one end thereof, each sheet having openings therein, flue tubes spaced from one another and secured to said sheets at said openings to provide passageways between said stack breeching and said second shell and also la second space for water and in communication with said first space, a horizontal water storage and steam drum above said first shell and having a steam outlet, first means, which are upcomers or downcomers, for the passage of water between said drum :and said first shell and second means for the passage of steam from said first shell into said drum, and uneans for feeding water to said boiler to maintain the desired water level in said drum. Said means may be operatively connected to said boiler through a conduit at an opening in the lower part of the first shell but preferably at one end of the drum.

The aforesaid horizontal boilers are relatively inexpensive to manufacture and install and the chances 0f the flue-tubes being torn away from their connecting sheets is greatly reduced if not substantially completely eliminated, and when in larger sizes are capable of producing in excess of 100,000 pounds of steam per hour. In addition wide variations in the sizes of the drum and the steam producing appaartus therefor are possible for the production of combinations of this invention of widely different steam outputs. And, the steam producing apparatus of the invention has a low water storage and may be quickly heated without creating substantial or intolerable stresses. Some of the foregoing results are achieved by the internal direct-firing of said second shell for supplying high intensity radiant heat thereto for quick heating of the water-wall between it and the first shell and after which the heated gases in a single pass travel through the ues of a convection section and thence directly or through an economizer convection section into and through the stack breeching in a single pass to heat the water between the outer shell and the flue tubes. Also in further and significant consequence, the temperature of the sheets or tubes at any particular vertical cross section at any particular time is lsubstantially the same so that at all times, even when there are frequent changes in the rate of firing, no substantial working of the ends of the tubes with respect to the sheets will occur, thereby greately, if not eliminating substantially completely, the development of leakage openings at the connections, generally welds, between the ends of the flues and their sheets.

In one of its more preferential aspects, the drum is vertically spaced from the first shell, the second means comprises at least one conduit secured to lsaid first shell at an opening therein located between vertical planes extending through the respective terminals of said second shell and disposed in the upper horizontally extending part or crown of said first shell and to an opening in the lower horizontal extending part of said drum, with the effective upper extremity of said conduit being at a level substantially above the effective upper limit of said first means and above the operating level of water in said drum and generally above the central longitudinal axis of said drum. In a still more preferential form, the second means includes at least another conduit, with said other conduit secured to said drum at an opening in the lower horizontally extending part thereof and to said first shell at an opening therein located between a pair of vertical planes extending through said sheets and disposed in the horizontally extending upper part or crown of the first shell, with the upper effective extremity of said other conduit also being at a level substantially above the operating level of water in said drum and generally above the central longitudinal axis of the drum. A steam separator is preferably disposed at the upper end of either one or yboth of said conduits and also the first means iS preferably disposed at the other end of the drum remote from the stack breeching.

In the preferred embodiment the drum has a feed water inlet at one end thereof and the first means is in communication with said drum at its other end wherein the water in said drum is much quieter and at substantially higher temperature than the water at the feed waterinlet end thereof. The first means comprises one or a plurality of and in this instance downcomers which are secured to said drum at said quiet water end thereof and preferably at openings in the horizontally extending lower part thereof and also to said first shell in the lower part thereof to provide a series continuous circuit between the water wall between the two shells, the water between the first shell and ues and that in the drum.

Also the drum is preferably spaced a substantial distance vertically from the first shell for ease and economy of manufacture and also if desired so that they may be shipped separately and readily assembled at the place of intended use. Moreover, this provides an effective apparatus wherein the steam producing portion may be on a particular deck of a ship for example and the drum on another deck above the first deck so that the shipspace may be used as is without requiring reconstruction should the drum and steam producing combination of such dimensions as not to be fitttable in the space between decks. Also, the steam producing portion may be in the 4basement or some other part of a building and the drum on the roof or other location thereabove.

Also in another aspect, there is means for continuously or intermittently feeding water-treating chemical to water in the drum at the feed water end thereof and also means for so feeding water-treating chemical to the water at the other end of said drum and/ or into said first means thus to provide separate chemical treatments in series relationship with the water circuit.

This dual feeding is very effective for the reason that the chemical supplied to the water at the feed water end which is at a lower temperature than that at the other end causes the precipitation of undesirable components therein at a progressively increasing rate due to the progressively increasing temperature of the water from the feed-water inlet end towards the other end of the drum, and in addition the quietness of the water being greater at that end opposite the feed-water end aids in the dropping out of such undesirable matter onto the bottom of the drum. And the chemical supplied to the water away from the feed Water end of the drum now treats water which has had a great proportion of undesirable components precipitated out so that the proportions of water treating material to the material to be removed may be mainained at a high level without requiring the use of amounts of the chemical treating material which are intolerable due to ecnomy or other reasons. This second addition may be of such composition as to precipitate out a maximum amount of water entrained materi'al therein prior to said material becoming contiguous with and depositing on the water side of the second shell.

The drum and the first shell are provided with appropriate blown-downs for removing the sludge or other material which has become deposited in the drum and outer shell. With this dual Water treatment the scale formation in the drum, on the convection tubes and shells is greatly reduced thereby increasing the life and efficiency of the boiler.

For increased efficiency and to reduce the proportion of undesirable components passing into the convection section and which may otherwise deposit in the tubes and/ or pass into and through the stack breeching, a plurality of high-heat resistant rings are spaced along the interior of the second shell and concentric therewith for the passage of the burning fuel therethrough and another combustion aid is disposed in said shell near the liue tubes and extends across the entire cross section of said shell. These rings attain incandescence and also act to impart a sequence of compression and expansion shock waves to the burning mass passing therethrough thereby increasing the collision rate between the air and fuel particles therein to aid in promoting combusion. The other combustion aid is in the form of an enlarged disc or circular element or shallow cylinder having a plurality of relatively small axial openings therethrough and simulating a honeycomb structure. This element like the rings is composed of alumina, silicon-carbide or other high heat resistant refractory material which aids in completion of the combustion of carbon containing, sulphur containing or other deleterious components, which otherwise would pass into and through said fiue tubes, whereby clean stack gases pass out of the stack breeching without the use of soot blowers. In addition the extent of the fiaming fuel mass continuously fed into the second shell from a fuel burner is controlled so that that mass while in the flaming condition does not fiow into said flue tubes and preferably terminates upstream from said tubes. And in the embodiment in which said honeycomb is employed, the flaming fuel mass does not extend beyond the downstream side of said honeycomb but may extend into said honeycomb.

Also a burner apparatus, which may be conventional or not is preferably coupled with the second shell to internaly direct-fire same, and the flues may be either conventional or novel as shown in certain embodiments illustrated and described. The burner apparatus is capable of feeding a mass of burning fuel and air into said second shell and towards the fiue tubes. The fuel used may be of any desired type, liquid, gas and/or solid. As the burning fuel mass initially enters the second shell it gives up considerable heat by radiation to said second shell and also tends to fill the space so that some hot gas is cooled at the internal wall of the second shell and this gas travels along the shell and against one of the refractory rings where it is restored to and mixed with the central flaming mass passing through that ring. Repetition of the aforesaid occurs with each space and each ring. The honeycomb also serves the aforesaid purposes. The distance between these elements is preferably no greater than 4 feet, and generally 1-4 feet apart. At high firing this flaming burning mass extends along the length of said second shell and terminates upstream of the fiue tubes and preferably in the honeycomb element so that there is substantially no flame on the downstream side of the honeycomb element and the non-flaming hot gases therefrom and downstream of said element are substantially free of noxious gases, soot or other depositable material and now pass through the tubes to supply heat thereto by convection and ultimately to said stack breeching and out of the discharge opening therein to a stack.

To further increase efficiency and decrease the size as well as the water storage of the novel boilers for a particular output, the flue tubes are preferably of the novel type which are the subject matter of a separate application and are also herein described.

Description of drawings FIGS. 1a and 1b together represent a vertical cross sectional view of an embodiment of a novel boiler of this invention.

FIGS. 2-4 are vertical cross sectional views taken on respective lines II-II, III-IIL and IV-IV of PIG. la in the direction of the arrows.

FIG. 5 is an enlarged cross sectional view of a novel extended surface flue tube shown in FIG. 1a and 1b.

FIG. 6 is a cross-sectional view of another embodiment of a novel extended surface ue tube.

Description of the preferred embodiment Some of the specific embodiments of this invention comprise a horizontal boiler 10 comprising a horizontal elongated cylindrical boiler shell 11 having a horizontal elongated cylindrical shell 12 extending therein and being concentric therewith to provide a relatively narrow space or water-wall 13 therebetween. An annular closure flange 14 integral with and extending inwardly from one extremity of shell 11 is sealed by welding to the outer surface of shell 12. Disposed in said shell 11 at the other end thereof is a first circular disc or sheet 15 whose entire outer periphery is sealed by welding to the interior surface of shell 11. A circular disc or sheet 16 is spaced a considerable distance from sheet 15, is of a diameter less than that of sheet 15 and is sealed to shell 12 by welding at its entire outer periphery. Said sheets are concentrically disposed with respect to each other and shells 11 and 12 and have spaced aligned openings for accommodating flue tubes 17 extending therebetween and sealed thereto by welding at said openings to provide a convection section 18 having space 19 for water and in communication with the space 13. The length of the space or water wall 13 is at least 40% that of space 19 and the radial distance between shells 11 and 12 is preferably about 2" to about 12, depending upon the boiler size dictated by steam output.

A conduit 20 is secured to shell 11 at an opening therein in the lower horizontally extending part thereof at one end thereof and to a pair of conduits or water downcomers whereby said downcomers are in communication with space 13 through conduit 20. A pair of conduits 21 are also secured to shell 11 at respective openings therein in the lower horizontally extending part thereof, with one being in direct communication with space 13 and the other in direct communication with space 19, and each is connected to a blow down valve not shown so that blow down may be effected to remove sludge which may have become accumulated in space 13 and/or space 19. Three vertically extending steam risers or conduits 22, 23 and 24 are weld sealed to shell 11 at openings in the upper horizontally extending part thereof; with conduits 22 and 23 located between a pair of vertical planes extending through the respective ends of shell 12 and both being in direct communication with the space 13; and with conduit 24 located between a pair of vertical planes extending through the respective sheets 15 and 16 and being in direct communication with space 19. These steam risers are of any desirable height depending upon the available space, the compactness desired and other considerations.

An economizer ue tube convection section 25 is disposed in alignment with the first convection section, and consists of a shell 26 of the same diameter as shell 11, with one extremity thereof welded to an extremity of shell 11.

A pair of discs or sheets 27 and 28 same as sheet 15 are seal welded to the interior of shell 26 at the entire outer periphery, and have a plurality of tine tubes 29, same as tubes 17, welded thereto at openings therein. Disposed in shell 26 are a plurality of vertically disposed baille or divider plates 30 spaced from each other and weld sealed at their entire outer curvelinear peripheral portions to the interior of shell 26, and clearance drilled for the tubes 29 which pass therethrough. Successive plates 30 terminate at different vertical levels, with one terminating in the lower part of shell 26, the next in the upper part of the shell and the next in the lower part of the shell as shown in the drawings for the purposes of illustration. Thus four compartments 32 are formed which are in communication with each other substantially only in the path shown by the arrows in shell 26 so that an elongated tlow path is provided for the heating of water flowing from one end of shell 26 to the other. The shell 26 has an inlet 33 for admitting water to be heated therein and an outlet 34 for discharge of the heated water therefrom after its passage through the elongated path in section 25.

One end of a Stack breeching 35, having an opening therein for the discharge of flue gases to a stack is sealed by welding to the other end of the shell 26 of the economizer 25 so as to be connected with the shell 11 of boiler 10 through section 26. However, the economizer 25 may be omitted if Idesired and the stack breeching may be seal welded directly to the shell 11 for connection therewith. Located in one end of shell 12 away from sheet 16 is a high heat resistant refractory ring or annulus 40 of appreciable and considerable thickness, composed of alumina, silicon carbide or the like and having an enlarged central opening 41 therethrough. Ring 40 is -concentrically disposed with respect to shell 12 and its outer surface is sealed to the inner surface of shell 12. Located in the other end of shell 12 and space d from the sheet 16 is a like heat resistant refractory circular element or shallow cylinder 44 having a large number of relatively small openings 45 therethrough which may be of any desired cross sectional configuration, square, hexagonal, circular, etc. and this element 44 I therefore call honeycomb. Element 44 also is sealed at its outer surface to the shell 12 and is concentric therewith. Disposed between and spaced from ring 40 and honeycomb 44, concentric therewith and also sealed to shell 12 are a plurality of like heat resistant refractory rings 46 and 48 which have enlarged central openings 47 and 49 respectively. The radial thickness of each ring 40, `46 and 48 is in the range of about 4"-8" and the axial thickness of each of them is in the range of about 6-12", and the axial thickness of the honeycomb is in the range of 6-12". The axial distance between opposing faces of adjacent refractory elements is 1'-4' for imposing repetitive shock waves to the flaming mass as well as repetitively clearing cold gases from the wall of shell 12.

Coupled with shell 12 is a burner apparatus 50 which may be of any suitable design and for example may be of any of those disclosed in my copending U.S. patent application Ser. No. 548,541 of May 9, 1966 and in this embodiment is one of them. The apparatus 50 comprises a pair of substantially imperforate refractory chambers 52 and 54 in communication with each other and having outlet openings 56 and 57 and one of them has an air-fuel nozzle 60 operatively associated therewith. Extending downstream of the chambers is a ceramic member 62 having a large number of passageways 63 for combustion air. The open end of member 62 extends into ring 40 and is encircled by an angle ring 65 which makes a sealing t therebetween and -part thereof abuts against an annular connecting ring 66 secured to ring 40 by stud bolts. Secured to the sealing ring is an air box 68 having a high volume air blower not shown, operatively associated therewith for supplying combustion air into member 62 through passageways 63. The nozzle in this particular embodiment shown has fed thereto air at about -350 ft./s'ec. from an about 5 p.s.i. air compressor and also fuel oil so that a stream of atomized fuel and air is Idischarged from the nozzle. A pilot light gas supplying conduit 70 and electrical supply cable 71 for a spark plug are carried by box 68 and are associated for lighting-olf in the chamber 54 the air-fuel stream from the nozzle.

The entire assembly before described, and those assemblies with or without either or both the economizer 25 and apparatus 50 may be produced and shipped as a single package and they may be supported by the use of any convenient means such as :an angle footings 73 to which are locked the ends of inverted U tie bars 74 which extend around shell 11. The outer surface of the shell 11 as well as that of shell 26 when the economizer 25 is used is covered with a layer 75 of suitable insulating material such as asbestos or the like.

Disposed at a level which is a considerable distance above that of shell 11 is a horizontal steam drum 80 which is in the form of au elongated cylindrical shell 81 with closures 82 and`83 integral therewith at the outer extremities thereof. The closure 83 has an enlarged manhole opening therein and a cover 85 which is movable to open or closed position by a yoke and screw arrangement 86. Below the manhole opening is a smaller opening in closure 83 to which is secured a feed water conduit 84 thereat. Between those two openings is a still smaller opening in closure 83 to which is secured one end of a Water treating material conduit 88 thereat and the other end is connected to a source of said water treating material. Instead of having said still smaller opening in closure 83, such an opening may be provided in the feed water inlet 84 instead for connection of conduit 88 to the inlet 84. The drum 80 has a plurality of conduits 90 connected to safety valve not shown, conduits 92 connected to steam pressure gauges also not shown, and an enlarged opening at the upper crown thereof at which is secured a steam outlet conduit 95 which is connected to any desired load, such as a turbine, etc. Closure 82 has a pair of conduits 96 connected to a water gauge not shown and a conduit 98 having one end secured thereto at an opening therein substantially below the operating water level in the drum and preferably near the bottom, and its other end is connected to a source of Water treating material. Associated with the conduits 88 and 98 are metering pumps or other conventional devices for intermittently or continuously feeding at predetermined rates the material from said sources. The water treating materials fed to the Water through conduits 88 and 98 may be of any desirable compositions, generally dictated by the presence of the undesirable components and percentages thereof in the Water at the respective ends of the drum. Shell 81 has a vent conduit 93 connected to a valve not shown.

Cylinder 81 has three openings therein in the lower part thereof and spaced horizontally from one another. The risers 22-24 extend through said openings, are sealed to cylinder 81 thereat and extend into the drum 80. These risers may be the sole support or aid in supporting and maintaining drum 80 in position above shell 11. The length of the risers is optional depending upon the distance of drum 80 from shell 11 but in all cases the effective upper level of the risers is a substantial distance vertically above the operating water level in the drum and preferably also above the horizontal central axis of the drum. The distance between the drum and shell 11 is at least about one foot and up to one hundred feet or more depending upon the vertical location of one with respect to the other and obviously the length of the risers are to some degree dependent thereon.

The cylinder 81 has a pair of oppositely disposed openings in the lower part thereof for accommodating the downcomers 99 which are secured thereat to cylinder 81 for the passage of water from the drum into the space 13 thereby being a series water circuit.

The ue tubes may be of any of the types known to the art and each of them may be merely a hollow cylinder, or such a cylinder having a plurality of narrow and thin reactangular elements secured thereto along their longitudinal edges to provide vanes therein. However, I prefer to empoly my novel tubes 17 and 29 shown in the drawings. Each of the tubes consists of an outer hollow cylinder 100, a smaller hollow cylinder 101 extending therein centrally thereof and a plurality, and as shown in FIG. 5, eight still smaller hollow equi-diameter cylinders 102 extending in cylinder 100 and between cylinders 100 and 101. These cylinders 102 are in force tit or in inteference fitting relation to cylinders 100 and 101 and also in relation to each other throughout substantially their entire lengths. All of the cylinders may be of the same composition and therefore having the same coefficient of thermal expansion, or cylinder 100 may be of a composition differing from that of cylinder 101 and/or cylinders 102 so that its cotlicient of thermal expansion may be different from that of cylinder 101 and/or cylinders 102. By employing such combinations wherein at least 100, 101 or 102 appropriately dilfers from at least one of the others, a tit may be more easily effected when the cylinders are at room temperature and when at elevated temperature of use a greater pressure is exerted between adjacent tubes to aid in heat transfer.

The more preferred embodiment of my novel flue tubes is that shown in cross section of FIG. 6 wherein only seven tubes are in the outer cylinder 100, with six equidiameter cylinders 102 between it and the central cylinder 101 and arranged as before in force or interference lit, with each of the cylinders 102 being in contact linearly throughout the entire lengths thereof with each other anld cylinders 100 and 101. Also instead of a central cylinder 100, a tube of appropriate polygonal cross section may be substituted therefor, for example an eight side and six side tube may be substituted respectively for tubes 101 shown in FIGS. 5 and 6. Also, it is preferable that each of such sides be of an external conguration as to present an elongated shallow surface throughout the entire length thereof for receiving a tube 102.

The overall cross sectional area or the outside diameter of the honeycomb 44 is at least 75% of the internal cross sectional area or the internal diameter of shell 12. The honeycomb 44 may be a unitary single cast element of the see or non-see through type, with the equivalent internal diameter of openings 45 being in the range of about W16 inch to 1 inch. Or, it may consist of a plurality of ceramic tubes arranged side by side as shown in FIG. 3 and having equivalent internal in the range above set forth. In any case the space between the inner wall of shell 12 and the outer surface of the honeycomb 44 is filled with refractory cement 94, to maintain the honeycomb 44 in position and more importantly, to prevent the flaming material from passing between the honeycomb 44 and shell 12 thereat thereby preventing the chilling of any ame ends at the cold wall of shell 12 adjacent said honeycomb.

Also if desired, a plurality, rather than one honeycomb 44 as shown, may be located in the downstream end of shell 12 and between sheet 16 and ring 48 and spaced from each other.

In the assembly before described, the sheet 15 is located at the downstream end of shell 11, sheet 16 is located at the downstream end of shell or furnace 12 and the honeycomb 44 is located in the downstream end of shell or furnace 12 and is spaced from sheet 16, and the convection section 18 and 25 and stack breeching 35 are all in substantially horizontal alignment with the shell or furnace 12.

The operation of the apparatus is as follows: The assembly shown in FIG. 1, is in fixed location and horizontally disposed as shown. Then, water is admitted into the assembly via the feed water inlet 84 to lill the spaces 13 and 19 and provide water in the drum to an appropriate level and in communication with the water in those spaces through the downcomers 99 and the drum is connected through conduit to a load. The apparatus 50 is made operating whereby a flaming mass of burning fuel and air is produced and extends through openings 41, 47 and 49 and at high firing terminates in the honeycomb 44 and then hot gases, which are not in flaming condition downstream of element 44, pass into and through tubes 17 to heat same and finally through tubes 26 if used to heat same and finally through the stack breechng. This flaming mass is continuously so mainta-ined and the radiant heat therefrom causes the rings and honeycomb to become incandescent and also causes the shell 12 to become hot very quickly whereby steam is quickly generated in the water wall 13 and passes through the water in the risers 22 and 23, and then the hot gases not in flaming condition and emanating from honeycomb 44 pass through the tubes 17 for heating same to Iincrease the temperature of the water in space 19 to such temperature as to produce steam which passes through the water in riser 24. Then the gases pass from tubes 17 through the tubes in the economizer 25 and finally into and out of the stack breeching. Due to the high temperature attained by the rings the heat therefrom acts to shock the fiaming mass passing therethrough whereby the collision pattern and rate of collision between the fuel and air particles are modified for aiding combustion. Also due to the high temperature attained by the honeycomb, components containing carbon, sulphur or other elements and not yet completely burned or otherwise reacted upon cooling would be depositable or otherwise undesirable are burned or further oxidized or otherwise reacted therein so that the gases passing though the flue tubes and breech stacking are so clean that there is no necessity for soot blowers and the gases emanating from the stack breeching do not contain intolerable amounts of so-called air pollutants.

Upon continuing the heating, steam is being constantly generated in the spaces 13 and 19 and passes through the risers to the top of the drum and out of outlet 95 and simultaneously feed water at appropriate rate is being continuously admitted to the drum through the Ifeed water inlet to maintain appropriate water level in said drum and obviously to replace the water which was converted into steam in spaces 13 and 19. The water entering the drum at the inlet 84 is from the economizer if used or from a feed water heater. In any case, water treating materials are continuously fed into both ends of the drum. That fed into the feed water end thereof starts to react therewith thereat and reaction is continuous along the length of the drum and precipitation of undesirable components in the water continues so that the water as it reaches the other end of the drum is in a much quiter condition of undesirable components precipitated out and now resting on the bottom of the drum. This treated water in which practically all of the added material has been consumed now is subjected to a second treatment by the continuous feeding of water-treating material thereto through conduit 98. This water is at higher temperature than that at the feed water end and more undesirable material is precipitated out and some of the water-treating material added at this end passes through the downcomers into the lower part of space 13 which is at even higher temperature to aid in causing reaction for precipitation of even more undesirable material so that the water which enters the space 19 is in such good condition that the scaling of the flue tubes is greatly reduced. The precipitated material may be removed from the drum and shell 11 by blowing them down at appropriate times through the blow valves associated therewith. It is preferable that the water-treating materials be simultaneously and continuously fed into the drum throughout steam production.

Since certain changes in carrying out the above process and in the constructions set forth which embody the invention may be made Without departing from its scope, it is intended that all matter conained in the above descripion or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described, and all statements of the scope of the invention, which as a matter of language might be said to fall therebetween.

I claim:

1. A boiler comprising an elongated horizontal first shell, a stack breeching connected with one end of said shell and having a passageway for the passage of liue gas therefrom, a furnace comprising a horizontal second shell extending a substantial distance along the length of said first shell and spaced from said first shell to provide space for water therebetween, a convection section comprising a first sheet secured to said second shell at the downstream end thereof, a second sheet disposed between said first sheet and the outer wall of said stack breeching and secured to said first shell at the downstream end thereof, each of said sheets having openings therein, flue tubes spaced -from one another and secured to said sheets at said openings thereby providing passageways between said stack breeching and said second shell and also space for water and in communication with said first mentioned space, said second shell, convection section and stack breeching being in substantially horizontal alignment, a horizontal water storage and steam drum vertically spaced from said first shell and lhaving a steam outlet therein, first means for the passage of water between said drum and said first shell, second means for the pasage of steam into said drum from said first shell, said second means comprising at least one conduit secured to said first shell at an opening in the crown thereof and to said drum at an opening therein, said conduit extending upwardly in the interior of said drum, said first mentioned opening located between vertical planes extending through the respective terminals of said second shell, the upper effective extremity of said conduit being at a level a substantial distance vertically above the 4effective upper extremity of said first means, and vertically above the operating water level in said drum.

2. A boiler according to claim 1,

said second means comprising at least one other conduit, said other conduit secured to said first shell at an other opening in the crown thereof and to said drum at an other opening therein, said other conduit also extending upwardly in said drum, said third mentioned opening located between vertical planes extending through said sheets, the upper effective extremity of said other conduit being at a level a substantial distance above the operating water level in said drum and the effective upper extremity of said first means.

3. A boiler according to claim 2,

said second mentioned opening also located between said first mentioned vertical planes and said fourth mentioned opening also located between said second mentioned vertical planes.

4. A boiler according to claim 1,

a feed water conduit for conducting water to said boiler to maintain the water level in said drum, said first means comprising a conduit secured to said drum at an opening therein and to said first shell at an opening therein.

5. A boiler according to claim 1,

a feed water conduit at one end of said drum, said first means comprising a conduit secured to said drum at an opening in the lower part of the other end thereof and to said first shell at an opening in the other end thereof.

6. A boiler according to claim 1,

and a steam separator at the upper end of said conduit, said separator disposed substantially above the operating water level in said drum.

7. A boiler according to claim 5,

in combination with third means for feeding watertreating material to the water in said drum at the feed-water end thereof and fourth means for feeding water treating material to the water in the other end of said drum and/'or in said first mentioned means.

8. A boiler according to claim 1, and

a refractory element located in the downstream end of said second shell and having a plurality of openings therein providing passageways in communica- 11 12 tion with the spaces in said second shell on either and means at the other end of said second shell to side thereof, said element adapted to be heated to supply burning fuel into the interior of said second incandescence by heat liberated from fuel supplied shell to direct-tire said furnace. into the interior of said second shell, thereby aiding 12. A boiler according to claim 1, in combustion to reduce the extent of depositable 5 and an economizer convection section disposed bematerial reaching said ues and decrease the extween said stack breeching and said first sheet, said tent of harmful products in the fflue gases passing stack breeching and said convention sections in subthrough the stack breeching. stantially horizontal alignment with said second 9. A boiler according to claim 1, and shell. a plurality of refractory rings located in, supported 10 by and concentric with respect to said second shell, References Cited each of said rings having an enlarged opening there- UNITED STATES PATENTS in for the passage of flaming mass therethrough 5 4 346 8 6 whereby it is heated to incandescence by the heat 6 7/1 9 Tltus 122-88 liberated from said fuel said rings spaced in the 713068 11/1902 Cowley et al' 122408 XR 15 range of about 1 -to about 4 from each other to 1024058 4/1912 Brady 122-410 3 848 11/1912 Lee 122-423 impart a sequence of compression and expans1on 104 f u shockwaves to the amingmass 2,576,053 11/ 1951 Toner 12b-149 XR 10. A combination comprising a boiler according to 2910972 11/1959 Swaney 122408 XR claim 1, 20

and means at the other end of said second shell for KENNETH W'SPRAGUEPnmary Exammer supplying burning fuel into the interior of said Us C1 XR second shell to directre said furnace, 11. A combination of said boiler according to claim 9, 122-406, 492 

